Zenchak (1981)
Sexual partner preference of adult rams (Ovis aries) as affected by social experiences during rearing+
Is the term “low-response rams” a misnomer?
The term "low-response rams" could be considered a misnomer because it doesn't accurately reflect the underlying cause of their behavior.
While the term implies a lack of response to sexual stimuli, the study actually reveals that these rams exhibit a preference for same-sex partners rather than a genuine lack of response.
Does the evidence support Zenchak et al.’s (1981) conclusion that experiential factors alter adult sexual preference?
Yes, the evidence supports the conclusion that experiential factors, particularly engaging in sex-like behavior with other rams during rearing, alter adult sexual preference.
The study found that rams exhibiting low-response behavior had engaged in significantly more sex-like behavior during their development, leading to a preference for same-sex partners in adulthood.
Should we be surprised that “low-response” rams exhibit “sex-like” behaviors during their development that parallel what we see in adulthood?
It's not entirely surprising that low-response rams exhibit sex-like behaviors during development.
Sexual behavior often emerges during adolescence and can be influenced by social interactions and experiences during this critical period of development.
However, the specific manifestation of same-sex preferences in adulthood might not have been expected without understanding the underlying mechanisms.
What do you think the rationale is for using the term “sex-like behavior”? What are the implications of using this term?
The term "sex-like behavior" likely refers to behaviors resembling those observed in adult sexual interactions, such as mounting and courtship, but without the actual sexual intent
Using this term helps to describe the behaviors accurately without implying full sexual maturity or intent.
It highlights the similarity in behaviors observed during development and adulthood without overstating the nature of these interactions.
What did the choice tests (Part A study) conducted by Zenchak et al. (1981) involve?
The choice tests involved presenting adult rams with a tethered estrous ewe and a tethered ram to observe their sexual preferences.
The rams were given opportunities to express a preference by directing sexual behavior patterns toward one of the tethered animals.
How was preference measured during Zenchak et al.’s (1981) experiment?
Preference was measured by observing which tethered animal the rams directed their sexual behaviors towards and spending the majority of their time with.
Rams were considered to prefer a particular animal if they exhibited active courtship towards it and spent at least 66% of their time in its vicinity.
What was the overall finding from Part A of the study?
The overall finding from Part A was that normal rams preferred estrous ewes as sexual partners, while low-response rams preferred same-sex partners.
This suggests that the failure of some rams to mate with ewes is due to their preference for same-sex partners rather than a lack of response to sexual stimuli.
What was the purpose of Part B of the study?
The purpose of Part B was to investigate competitive behavior between normal and low-response rams over an estrous ewe.
The study aimed to understand how these different types of rams interacted in the presence of a sexually receptive female.
Part B of the study found that low-response rams interfered when normal-response rams showed interest in the ewe. Why do you think this happened?
Low-response rams likely interfered with normal-response rams due to social dominance or territorial behavior, rather than genuine sexual interest in the ewe.
Since low-response rams typically preferred same-sex partners, their interference may have been driven by factors unrelated to mating behavior, such as asserting dominance over other males.
Zenchak et al. (1981) state that “Because interference was also observed in low-response rams, the stimulus that elicited the activity was probably not sexual in origin, since these rams were clearly not interested in estrous ewes as sexual objects.” Do you agree with this interpretation of interference behavior by low-response rams?
Yes, this interpretation seems plausible. Since low-response rams were not interested in ewes as sexual objects, their interference behavior likely stemmed from other motivations, such as social dominance or territoriality.
This suggests that the stimulus prompting interference may not have been sexual in nature.
What evidence is there that olfactory cues influenced the test rams’ behavior?
The study mentions olfactory investigation of the ewe's body parts by the test rams, suggesting that olfactory cues may have influenced their behavior.
Rams sniffing the genital region of the ewe and then turning away to approach the tethered ram indicates some response to olfactory cues, even if they didn't exhibit sexual interest.
Zenchak et al. (1981) state: “… the stimulus that caused interference behavior may not have been the estrous ewe, but may have been the fact that another ram was engaging in a certain behavior.” Can you think of a way that this could be tested?.
One way to test whether interference behavior is prompted by the presence of another ram engaging in certain behaviors rather than the estrous ewe would be to conduct experiments where the behaviors of the test rams are observed in isolation from both ewes and other rams.
This would help isolate the specific stimuli that elicit interference behavior and determine whether it is directed towards certain behaviors or individuals.